1. Field of the Invention
The present invention relates to a system for automatically extinguishing embers in a gun tube or a cannon tube assembly (the terms cannon tube and gun tube are used interchangeably herein; cannon tube is used henceforth for brevity.) More particularly, the invention pertains to an automatic liquid spraying system for extinguishing burning embers and/or residue remaining in a field artillery cannon assembly after firing.
2. Description of the Prior Art
The United States military uses various techniques to extinguish burning embers with respect to its weapon gun systems. The Army uses various types of wash systems for its large caliber cannon tubes. For example, the Army uses a high pressure air wash system upon the completion of its firing of the Shillelagh missile from the M60A2 tank. The Navy uses various types of wash systems on its large caliber cannon tubes. A government contractor proposed a system that is capable of spraying air and/or water into the cannon tube. Further the contractor performed basic experiments on blowing cloth rags out of cannon tubes with high pressure air jets. Another contractor built a hand held manual bore swab with a self contained water supply. Another contractor suggested swabbing the breech area with a rammer or sponge mechanism.
3. Specific Prior Art
Patent No. 4,657,086 to Oscar Aanensen, issued Apr. 14, 1987, discloses a fire extinguishing system for use on a helcopter deck. The system has sets of nozzles to direct jets of foam (or water) to extinguish embers and wash away the foam.
4. Advantages Over the Prior Art
The present invention pertains to a liquid spraying system for extinguishing burning embers and residue remaining in a cannon tube after firing. The system includes an automatic assembly which sprays a liquid medium such as water or chemical foam liquified solution into the cannon tube assembly after every round of ammunition is fired. The liquid medium is sprayed coaxially into a cannon tube breech area and onto an obturator spindle axis with sufficient impingement force to completely extinguish and/or eliminate any burning ember and residue which may be present.
The present invention solves age old problems associated with extinguishing burning embers that remain after the firing of a cannon. The invention solves problems associated with washing, swabbing, or spraying the cannon tube assembly to extinguish burning embers before the next propelling charge is placed into the cannon tube. The invention solves problems which have plagued artillerymen in situations involving weapons firing semi-fixed powder charges (combustible powder bags separate from projectile.) The placement of an explosive charge onto a burning or smoldering ember can result in a spontaneous detonation of the newly inserted propelling charge or powder bag which in turn, may cause a high order detonation of the projectile. Explosions of this magnitude can be castatrophic for the immediate cannon crew and equipment.
This invention is vastly different from any previous system of accomplishing the swabbing procedure to extinguish burning embers. Past and current systems are based on stone age technology of placing a sponge/mop/absorbent material on the end of a ramming staff or rod and dipping it into a bucket of water and then proceeding to manually swab the cannon tube assembly until the embers and residue are extinguished. This wets and consequently extinguishes any burning embers which may ignite a subsequent powder charge placed on top of them. This problem has been tolerated by artillerymen for centuries, since pre Civil War days through both World Wars, Korea, Vietnam, and even Desert Shield. Past and present artillerymen have swabbed the cannon tube to extinguish the burning embers in much the same way. The science of guns, cannons, and artillery pieces has kept pace with today's technology in some areas and yet has remained virtually unchanged in the swabbing area--until the event of the present invention.
Even the Army's latest version in the family of M109 Howitzers, the M109A6 (HIP), is a paradox of technology with its high tech electronics systems including land navigation, ballistic computers, planned automated loader and ramming systems, and automated gun pointing devices to insure rapid accurate fire, and yet the crew still uses a bucket, ramming staff, and sponge to swab the cannon tube assembly between rounds. The tube swabbing task is labor intensive and time consuming for the crew in comparison to an automated system. The task may pose a significant safety hazard if not performed correctly, may introduce various amounts of liquid into the breech, and may reduce the effectiveness and speed of firing the howitzer in sustained operations.
5. Statement of the Invention
In one embodiment of the invention, the system utilizes external electric and pneumatic power sources. The electric power for the system's components is supplied by an independent electrical power source. The pneumatic pressure is supplied by an electric compressor (or a high pressure air bottle with step down regulator) for actuating a rotary actuator and a spray arm assembly, and for providing air over liquid pressure for delivery of the sprayed liquid medium. Electrically operated solenoid valves control the flow of both liquid and air for cycling of the system. Electronic micro switches and an adjustable timer provides phase signals for precise operation of the system within extremely close operating and timing parameters. The system is equipped with a fail safe pneumatic emergency return button for powered return of the spray arm in the event of an electrical malfunction, and is also equipped with a redundant spring assisted manual return for the spray arm in the event of a pneumatic failure as well. The spray arm is under a protective cover and incorporates a safety restraint bar for manual stoppage of the arm as it returns to its starting or home position.
In another embodiment of the invention, the system utilizes an internal power source; that is, a self-powered hydraulic apparatus. This embodiment is based on principles of hydraulic fluid mechanics and simple mechanical type valves and actuating components for the transmission of liquid to a specially designed spraying mechanism. The system utilizes hydraulic pressure supplied by the cannon's recoiling action for the actuation of positioning mechanisms for a cannontube spray arm and an obturator spray arm, and to also provide hydraulic pressure for delivery of the sprayed liquid. In this embodiment, the system is entirely independent of any external power sources and is based on the basic operating principle of a common squirt gun. The squirt gun unit which operates after the cannon is fired, utilizes the kinetic energy of the cannon tube's recoil for its power. The spring loaded cylinder piston unit provides both suction and pressure of liquid for transfer into the various actuating mechanisms and eventually to the spray nozzles themselves.
Accordingly, under either embodiment of the invention, the system solves the prior art burning ember and residue problem by utilizing a spray assembly which automatically sprays liquid into the cannon tube assembly after every round has been fired. The spray assembly retracts to a safe position that allows the next loading to proceed. This is accomplished in a time frame of approximately 1.31 seconds with no human intervention. Accordingly, the system provides many improvements over prior art equipments employing buckets, ramming staffs, and sponge systems.